One inevitable problem of many existing filtering systems is the accumulation of sediments on the filtering element during filtration, blocking its porous surface and lowering the filtration rate until totally preventing it. Thus, plain filtration systems have to be treated occasionally by cleaning the used blocked filtering element or by replacing it with a clean one, which means interrupting and stopping the filtration process from time to time.
The present invention focuses on (but not limit itself to) the fields of filtration of liquids, irrigation water, recycling of sewage and industrial waste water, recycling of cooling towers water, filtration and purification of drinking water etc.
The aim of the present invention is to provide a high efficiency continuous liquid filtering apparatus having self-cleaning mechanism allowing the continuous filtering operation, i.e. without interrupting the supply of filtered liquid.
Self-cleaning filter devices are known in the art, but they are not efficient enough--in the filtration rate and in the self-cleaning quality. The filter elements used by the said known in the art devices are comprised of PVC support screens combined with one layer of screen mesh. The filter element void rate in such combination of screens is only about 60% of the filter surface, meaning bulky and inefficient filter element. Another problem in said filter elements is that during the filtration a significant amount of particles are trapped between the PVC support and the mesh, which reduces the cleaning efficiency and further reduces the void rate.
The apparatus of the present invention overcomes the abovementioned disadvantages, and increases the efficiency of the filtration process and the self cleaning of the continuous filtering apparatus, by using a unique combination of a cylindrical multi-layer sintered body of metallic screens as a filtering element, and an electro mechanical self-cleaning system.
Said cleaning system is based on a back and forth helical motion of a dirt collector having dirt suction members equipped with spraying nozzles. The spraying nozzles use the filtered liquid after being pressurized by a booster pump for vibrating and rinsing the sediments accumulated on the sintered filtering element, while the pressure-difference between the pressure of the liquid within the apparatus and the pressure of the free atmosphere outside of the apparatus is utilized as a suction force for the operation of the dirt suction members.